Folding laryngoscope and angularly adjustable and detachable joint therefor



Aug. 18, 1953 FOLDING LARYNGscPE AND ANGULARLY ADJUSTABLE Filed Feb. 12,1951 W N ALLYN ETAL AND DETACHABLE JOINT THEREFOR 3 Sheets-Sheet 1 8,1953 w N. ALLYN ETAL 2,649,087

FOLDING LARYNGSCOPE AND ANGULARLY ADJUSTABLE AND DETACHABLE JOINTTHEREFOR Filed Feb. 12. 1951 3 S heetsSheec 2 .7 the Aug. 18, 1953 w. N.ALLYN ET AL 2,

FOLDING LARYNGQSCOPE AND ANGULARLY ADJUSTABLE AND DETACHABLE JOINTTHEREFOR Filed Feb. 12, 1951 3 Sheets-Sheet 3 FIG. 10. 46

& F1 cs. 15. FIG

Patented Aug. 18, 1953 UNITED STATES PATENT OFFICE FOLDING LARYNGOSCOPEAND AN GULAR- LY ADJUSTABLE AND DETACHABLE JOINT THEREFOR ApplicationFebruary 12, 1951, Serial No. 210,598

23 Claims.

The present invention relates to laryngoscopes, pharyngoscopes, and thelike, and more particularly to an improved angularly adjustable,detachable joint connection between the blade and handle of suchinstruments.

Laryngeal and pharyngeal speculums are employed to depress theepiglottis at the base of the tongue, for illuminating the larynx,pharynx and adjacent areas for purposes of diagnostic examination,therapeutics, intra-nasal or intra-trachael intubations,anaesthetization, or for any other purpose that requires access toand/or illumination of the posterior oral cavity, larynx, pharynx, orelsewhere, as necessary in each individual case.

It is desirable to have an instrument of this type that is capable ofrelative angular adjustment between the handle and blade, so that thepathologist, therapist or anaesthetist may assume a wide range ofpositions relative to the patient, as may be required in differentcases.

It is also desirable that the blade of the instrument be foldable to aposition closely adjacent to the handle so as to occupy a minimum ofspace for purposes of storage, and that the blade be readily detachablefor purposes of rapid and thorough sterilization, and for purposes ofinterchange with blades of difierent sizes and/or shapes.

Accordingly, it is an object of the present invention to provideinstruments of the aforementioned type with an improved joint connectionbetween the handle and blade sections whereby the blade section may bemore readily angularly adjusted relative to the handle section, andpositiVely locked in any of a plurality of selective 0perative positionsor in an inoperative folded position with the blade lying closelyadjacent to the handle.

Another object is to provide an angularly adjustable joint connectionwhich permits rapid and simple detachment of the handle and bladesections.

A further object is to provide an angularly adjustable, detachable jointconnection between the handle and blade sections of a laryngoscope orthe like, which includes means for automatically completing anelectrical circuit between the light bulb, usually carried by the blade,and the batteries or other power supplying means carried by the handle.

Still another object is to provide means for positively locking thehandle and blade sections against inadvertent angular movement when theinstrument is in use.

A still further object is to provide a joint connection forlaryngoscopes, pharyngoscopes and the like which is extremely simple andeasy to operate, relatively inexpensive to manufacture, and extremelystrong and durable.

Other objects and advantages will hereinafter become apparent and thenovel features of the invention defined in the appended claims.

In the drawings:

Figure 1 is a view in side elevation of a laryngoscope embodying theimproved hinge joint connection of this invention, with the blade shownin full lines in one of its operative positions, and also showing indotted lines the relative positions of the handle and blade sections asassumed when they are to be laterally separated or detached from eachother;

Figure 2 is a view in top plan of the laryngoscope of Figure 1, with thefree end of the blade broken away;

Figure '3 is an enlarged fragmentary view in side elevation of the hingejoint connection with the closure cap removed;

Figure 4 is an enlarged view in vertical section, as taken on the line4-4 of Figure 1;

Figure 5 is a view in vertical section, as taken on the line 5 of Figure4;

Figure 6 is an exploded view of the hinge joint connection, with certainof the parts broken away and shown in section;

Figure '7 is a view in vertical section, as taken on the line 11 ofFigure 4;

Figure 8 is a fragmentary view in elevation of a portion of the jointmember which is carried by the handle, with the splined pin or plungeromitted from this View;

Figure 9 is a view in perspective of the joint member which is carriedby the handle, and showing a fragmentary portion of the handle;

Figure 10 is an enlarged fragmentary view in elevation of the hingejoint showing one form of the joint safety lock, the safety lock beingshown in full lines in its locking position, and in broken lines in itsunlocking position;

Figure 11 is an enlarged fragmentary detail View in top plan, showingthe safety lock of Figure 10 in locking position;

Figure 12 is an enlarged fragmentary detail view in top plan, showingthe safety lock of Figure 10 in unlocking position, and showing inbroken lines the depressed position of the actuator button;

Figure 13 is a sectional detail view of the safety look, as taken on theline I3l3 of Figure 11;

Figure 14 is an enlarged fragmentary view in elevation of a modifiedform of hinge joint, with a portion broken away to show the details ofconstruction of a modified actuator button which serves also as thesafety lock upon rotation thereof Figure 15 is a view in horizontalsection, as

taken on the plane of the line l5|5 of Figure 14, showing the actuatorbutton in full lines in its safety unlocking position, and showing inbroken lines the safety locking position assumed by the actuator buttonupon rotation thereof;

Figure 16 is a vertical sectional view, as taken on the line l6-lfi ofFigure 14;

Figure 17 is a view in horizontal section, as taken on the line l'lll ofFigure 14; and

Figure 18 is a view in perspective of the actuator button shown inFigures l lthrough 1'7, and more particularly showing the interior formthereof, but on a slightly reduced scale.-

Like reference characters designate corresponding parts in the severalfigures of the drawings, wherein the instrument, for purposes ofillustration, has the form of a laryngoscope, as seen in Figure 1, andcomprises a handle I and a blade 2 which are interlockingly, detachablyand 'adjustably interconnected by means of a novel joint construction 3to which the present invention primarily relates.

The co-pending application of Cook and Becker, Serial No. 169,918, filedJune 23, 1950, discloses an instrument of this general type, and thepresent invention constitutes a substantial improvement over the jointconstruction of that application, since the present joint is more simpleand inexpensive to manufacture, attains greater ease of operation, andis much stronger and more durable.

The blade of the instrument may have any desired form, that form shownbeing purely illustrative, and is suitably secured to a frustoconicalhead member 4. The end of the head member 4 remote from the blade 2forms, as at 5, one of a pair of complementary, relatively rotatablejoint members, and the head member 4 and the blade'Z together constitutea detachable blade unit or section.

The handle I of the instrument is connected to a base member 6. The freeend of the base 6 forms, as at 6, a joint portion which is complementaryto the member 5, the handle I and base member 5 forming a handle unit orsection.

The portion 5 of the head 4 comprises an enlarged cylindrical jointmember having its central axis disposed at a right angle to the axis ofthe head member i, and is laterally offset from the latter axis so as tohave its inner face substantially flush with the median plane of thehead 4. Internally of the cylindrical joint member 5 is a radiallyinwardly extended locking ring '1 preferably formed integral therewith,the looking ring 1 being provided with circumferentially spaced teeth orsplines 8. The inner surface of the cylinder 5 inwardly of the lockingring 1 is provided with an annular groove 9 and a pair of diametricallyopposed communicating slots I which extend longitudinally inward fromthe groove 9 to define a so-called bayonet slot. The outer open end ofthe cylindrical enlargement is adapted to receive a closure or cap I Ihaving a collar l2 which may be suitably positioned within the member 5,as by means of a tight friction fit or the like (see Figure 4) Themating or complementary member 6' on the base portion 6 of the handleunit is also in the form of a cylindrical enlargement which is laterallyoffset so as to form a shoulder [3 having its inner face substantiallyflush with the median plane of the base 6, said shoulder being adaptedto butt up against the inner face of the cylinder 5 on assembly of thejoint. The cylindrical member 6' has a cylindrical projection I4 ofreduced a locking screw 26 (see Figure 4) size adapted to extend intothe member ,5, as best seen in Figure 4, into abutting engagement withthe locking ringl, the projection I4 being provided with a pair ofdiametrically opposite, outwardly extending pins 9' which are adapted topa'ss'throughthe slots in in the inner surface of the member'5, and intoregistry with the annular groove 9 so that the two complementary members5, 6' may be interlockingly engaged with each other upon relativerotation thereof, or relative angular movement between the handle I andthe blade .2'toany position other than that when 'the pins 9', 9 are inregistry with the slots [0, ID.

A common opening. or bore I5 extends through the cylindrical members 6'and I4, and the inner faces of these members are provided withlongitudinally extended teeth or splines I6, one of the splines I6 beingcut back, as at l6, for a predetermined distance (see Figure 6).

A reciprocable plunger or pin H is adapted to be shiftably positionedwithin the opening 15 and is provided with circumferentially spaced,longitudinally extended splines or teeth lt-for cooperativeinterengagement with the splines I6 inthe cylindrical members 6' and I4and with the splines 8 in the locking ring I. Adjacent to one endthereof, the plunger pin I1 is reduced in diameter, as at 19, thusleaving a pair ofaxially spaced splined sections 20, 2| thereon, and anintermediate annular recess between these "splined sections 2Q,'2|,'fora purpose that will be more fully explained hereinafter in thedescription of operation. Between two of the teeth IS on thesplined'section-20 of the plunger pin IT is a radially outwardlyextended pin or stop 22, which in assembly is adapted to be positionedin the space is left by cuttingba'ck one of the this purpose. The buttonor cap ZAmay be locked in adjusted position on the neck 23 by means of Atapered coil spring 21 is interposed between the cylindrical jointmember 6' and the cap as for urging the cap away from the joint member6, the small end of the coil spring 21 being centered about theprojection 25 and disposed in abuttingrelation to the inner surface ofthe cap-24, and the large end of the coil spring 21 being seated in anannular groove ZB in the outer face of the cylindrical joint member'fiopposed to the cap 24.

As best seen in Figure 4, the spring ZTurges the plunger or pin I? tothe left until the stop pin22 between two of the teeth !8 on the splinedsection 20 of plunger ll butts up against the spline [6 which has beencut backat IS. The relative position of the spline section 2! withrespect to the locking ring I when the plunger 1'! has reached its limitof movement to the left is such that the splines 8 and 21 on therespective parts are squarely interengaged, thus locking the head 4 andthe base 6 against relative angular movement and in a selective positionof adjustment. The angular relationship between the head 4 and the base6 may be readily changed, however, by pushingthe plunger button oractuator 24 to the right, with consequent shifting 'of the plunger H totheright until the spline section 2| completely disengages from thelocking ring 1 and the reduced section I9 of the plunger I7 is locatedwithin the locking ring I, whereupon the complementary joint members arefree to rotate relative to each other. In order to allow the plunger I!to be shifted a suificient distance to the right when it is desired toadjust the angular relation of the instrument, the cap or plunger button24 is provided with a chordal recess 3|] so that the lower portion ofthe cap 24 will not abut against the adjacent portion of the base member6.

In use,,the therapist or other operator often grasps the instrument inthe area of the joint 3, and thus may inadvertently depress the plungerH to such an extent that the angular adjustment of the instrument may bechanged. This is very undesirable, particularly having in View thesubstantial forceas much as 150 pounds, that the operator often mustapply to the instrument. Therefore, a safety lock is preferabl providedto positively lock the plunger l1 against inadvertent shifting movement,and in one embodiment, as seen in Figures 1 to 13, this safety lockcomprises a pivoted cam lock, designated generally at 3!, suitablysecured to the outer peripheral wall of the cylindrical joint member 5'by means of a screw 32 or the like. The cam lock 3| includes anoperating knob or projection 33, and its inner face is cut back, as at34.

' As best seen in Figures 10 to 12, when the cam lock 3| is in theposition shown in full lines in Figures 10 and 11, it engages theplunger button 24 and prevents shifting movement thereof until the cutback portion 34 is turned around to face the plunger button 24, as seenin broken lines in Figure 10, and in full lines in Figure 12, at whichtime the plunger button 24 is rendered free for movement towards thejoint 3, as shown in broken lines in Figure 12.

Figures 14 to 18 show another embodiment of the safety lock feature ofthis invention, wherein the actuator button is adapted to be rotatablyshifted relative to the joint so as to cause the annular skirt thereofto butt up against the base portion 6 of the handle section and therebyprevent inadvertent depression of the actuator button. In this form, theconnection between the actuator button and the plunger pin is modifiedslightly from that form shown in Figures 1 to 13,

but the joint construction is identical. Therefore, the joint parts inFigures 14 to 18 have been given corresponding reference characters, andthe modified actuator button and safety lock means have been designatedby new reference characters.

Referring now to Figures 14 to 18, it is seen that the actuator button5!} includes an annular skirt 5| and an internal boss or projection 52which is freely rotatably mounted on the reduced end 53 of the plungerpin I1 and is secured thereto by means of a screw 55 having acylindrical head portion 55 which is received in a complemental recess56 in the actuator 55, thus allowing the actuator 55 to be rotatedrelative to the plunger IT. A washer 54 is preferably interposed betweenthe cylindrical head 55 of the screw 54 and the portion 53 of theplunger pin 1, this washer acting to bind the screw 54 against the pinll so as to prevent its rotation with the actuator 50, that otherwisewould loosen the screw.

When the joint is locked by the spline section 2| on the pin I and thesplined locking ring I in a selected position of angular adjustment, theplunger may be shifted out of joint-locking position by depressing theactuator button 50, the chordal recess 51 in the skirt 5| permitting theactuator to move past the adjacent surface of the base portion 6.However, due to the fact that this actuator is rotatable, it may beturned to such a position that the skirt 5| thereof abuts against theadjacent portion of the base 6, as is represented by the broken lines inFigure 15, thus prohibiting depression of the actuator. The outerperipheral surface of the skirt 5| is preferably roughened or knurled,as at 5|, to permit it to be readily and easily turned by the operatorsfingers without slippage.

Means cooperative between the portion 53 of the plunger pin l1 and theboss 52 is provided to limit the extent of rotative movement of theactuator button 55, this cooperative means preferably comprising aradially extended stop pin 58 carried by the reduced portion 53 of theplunger l1 and engageable with the opposed faces 59, 60 of the boss 52at opposite'ends of a circumferential recess 6| in the boss 52 intowhich the stop pin 58 projects.

The relationship of the stop pin 58 and the recess 6| is such thatrotation of the actuator button 50 in a counterclockwise direction, asseen in Figure 16, causes the face 60 of the boss 52 at the end of theslot 6| to engage the stop pin 58, and in this position the actuator 5|]is free to be laterally or axially shifted to unlock the joint 3 byvirtue of the chordal recess 5'! in the skirt 5| of the actuator beingdirectly registered with the base portion 5. Upon reverse rotation ofthe actuator 50, the, face 59 of the boss 52 which is at the oppositeend of the recess 6| from the face will engage the stop pin 58, and theactuator 50 will be so positioned that the skirt 5| thereof will abutagainst the base portion 6, as shown in broken lines in Figure 15, thuspreventing lateral shifting movement of the actuator 50 in a directionto unlock the joint 3.

The instrument is also preferably provided with suitable means forenergizing a light bulb 35 carried adjacent to the outer end of theblade 2, when the instrument is in at least one of its operativepositions, this position being designated L in Figure 1, and fordeenergizing the light when the instrument is in its inoperative foldedposition or in its separable position S shown in broken lines, or anyother position or positions within its range of adjustment, but it mustbe understood that the circuit making instrumentalities may be readilymodified to effect illumination of the bulb 35 in any or all of thevarious angular positions assumed by the instrument without departingfrom the spirit of this invention.

The means for effecting the energization or deenergization of the lightbulb 35 includes a 1 suitable number of flashlight batteries 35 carriedin the handle I, as is customary in the art, the handle "being suitablyattached to and closed by the base member 5, as by means of screws 31.Electrical contact is made with the batteries 36 by a contact 38suitably positioned in a vertical .bore 39 in the base 5 and insulatedtherefrom as at 40. An insulated conductor M extends from the contact 38through the bore 39 and thence through a passage 42 extending throughthe cylinclrical joint member 6, and is connected to a contact shoe 43which is mounted in an insulating block 44 which is secured in anarcuate groove in the periphery of the cylindrical member 6 by means ofscrews 44' or the like.

Adapted for cooperation with the contact shoe 43 is a spring-loaded ballcontact assembly 45 to occupy a minimum of storage space.

"carried in an insulating block which is fixed in-a groove in the flatface l of the head, as

by means of screws 46' or the like. Connected to the ball contactassembly 15, and passing through the hollowhead 4 is a second insulatedconductor -41, whichis passed to the exterior-of the head member 1adjacent the point. of juncture of the head with the blade 2 (seeFigure 1) as at 48, and then extends through a small tube 49 extendingalong the outer side of the blade 2 to the light 35. Ground contact forthe other side of the circuit is made through the metal parts of theinstrument, as is conventional in self-contained and portableilluminated devices.

As best seen in Figure 5, the ball contact assembly 45, the'contact shoe43, and their respective insulating blocks are so located and arrangedin the head 5 andthe cylindrical joint member 6', respectively, of theassembledinstrument that they do not interfere in any way with thelateral separation of the joint 3 when the .bladeZ is shifted to theposition designated S in Figure 1, after depressing the actuator button24 or 5D in the manner hereinbefore described andcorresponding to theoperation for permitting any angular adjustment of the blade relative tothe handle.

While the instrument of this invention has been described and shown ascarrying batteries in the handle, it it within the purview thereof tohave means for plugging in to a house current supply in lieu thereof.

An instrument madein accordance with this invention will normallybe-stored in a completely folded position, i. e., with the blade 2 swungto a position closely adjacent the handle I, so as When the instrumentis to be utilized, it is merely necessary for the operator to press theactuator button 24 or 50, as the case may be, inwardly, thusshifting theplunger pin I! to the right, as seen in Figure 4, thereby disengagingthe splines I8 on the splined section 2! from the splines 8 in thelocking ring I, thus rendering theblade and handle unit free forrelative angular movement. Then the blade is swung away from the handle,the ball contact 45 riding up over the insulating block 44 intoengagement with the contact shoe 43, and efiecting energization of thelamp 35. Upon release of the plunger-button 24 or .50, the splinedsection 21 will be urged back into engagement with the locking ring 1 bythespring 21, the stop pin 22 limiting this movement and assuring properregistration of these splined members. The joint is accordingly stronglyand rigidly locked in the, position of. angular adjustment designated Lin Figure 1, or in any other selective position,.according to the numberand spacing of the splines l8 and 8. The operator may then rotate thesafety lock 3| to the position shown in Figures 1, 2 and 3, or he mayrotate the actuator 50 to the position shown in broken lines in Figure15, to obviate inadvertent depression of the actuator button 24 or 50during use of the instrument.

Thedegree of angular adjustment attainable by the instrument of thisinvention is limited only by the size and number of the complementarysplines 8, I8, and the instrument may be locked in any positionintermediate the fully folded, storingposition to the extreme limit ofits relative movement in the opposite direction, and, by the same token,the electric contact shoe 43 may be, if desired, extending to such anextent that the lamp 35 will be energized in all of these operativepositions of adjustment with the exception of the fully folded position.Suitable stops may be provided, if desired, to limit the extent ofangular adjustment in either or both directions without departing fromthe spirit of this invention, as by placing suitable stops or lugs inthe desired position in the annular groove 9 in the inner periphery ofthe cylindrical joint member 5.

When it is desirable to completely disengage the blade unit from thehandle unit for purposes of sterilization or for changing to otherblades, the cam lock 31 is turned so that the cut back portion 34thereof is opposed to the plunger button 24, or the actuator '50 isrotated to its position with the chordal recess '51 in register with thebase portion =6, and the same-procedure as has been hereinbeforedescribed is followed, except that the blade unit is swung to theposition designated S, at which position the opposed pins 9 in theannular groove 9 are in alignment with the slots I0 and the blade andhandle units may be laterally separated. In all other positions,however, the joint is held against lateral separation by the pins 9'being confined in the annular groove 9, the substantially close fitbetween thepins 9 and the groove 9 preventing any lateral play betweenthe joint parts.

While the instrument shown in the accompanying drawings is adapted to beseparated when it is in the position S, it should be understood that theseparable position may be varied as'desired, by merely varying therespective angular positions of the slots [0 in the inner periphery ofthe member 5 and the pins 9? on the cylindrical portion M of themember-6.

It is to be understood that the term laryngoscope as used in theforegoing description and in the appended claims, is intended to beconstrued in a broad sense as embracing phary escopes and various otherinstruments of an equivalent type wherein a blade or other oper ativepart is to be adjusted angularly relative to ahandle member or othercomparable support.

While the specific details have been herein shown and described, theinvention is not confined thereto, as changes and alterations may bemade without departing from the spirit thereof as defined in theappended claims.

What is claimed is:

l. A laryngoscope, comprising a'handle section, a blade section, andmeans hingedly interconnecting the sections including complementalrelatively rotatable members for enabling. said blade section to beangularly adjusted relative to said handle section, shiftable meanscarried by the firstmentioned means for positively locking said sectionsin selective adjusted angular positions, and means carried by saidshiftable means and engageable with a relatively fixed abutting part ofone of said rotatable members for releasably locking said shiftablemeans in locking relation with said sections to prevent the same frombeing shifted in one direction.

2. A laryngoscope, comprising a handle section, a blade section, andmeans hingedly interconnecting the sections including complementalrelatively rotatable members for enabling said blade section to beangularly adjusted relative to said handle section, shiftable meanscarried by the first-mentioned means for positively locking saidsections in selective adjusted angular positions, means carried by saidshiftable means and engageable with a relatively'fixed abutting part ofone of -said rotatable members for selectively locking said shiftablemeans in locking relation with said sections to prevent the same frombeing shifted in one direction, and cooperatively interengaged parts insaid hinge means, one of said parts being provided with meansdisengageable from the other part for enabling lateral separation of thesections aforesaid when the sections are in one predetermined positionrelat-ve to each other while interlocking said secti-f-ns together inevery other relative position.

3. A laryngoscope, comprising a handle section, a blade section, andmeans hingedly interconnecting the sections including complementalrelatively rotatable members for enabling said blade section to beangularly adjusted relative to said handle section, means within saidcomplemental members normally interlocking the complemental members inselective adjusted angular positions but being shiftable out ofinterlocking relation therewith for permitting angular adjustmentthereof, and means carried by said shiftable means and engageable with arelatively fixed abutting part of one of said rotatable members forselectively locking said shiftable means in interlocking relation withsaid complemental members to prevent the same from being shifted in onedirection.

4. A laryngoscope, comprising a handle section, a blade section andmeans hingedly interconnecting the sections including complementalrelatively rotatable members for enabling said blade section to beangularly adjusted relative to said handle section, means within saidcomplemental members normally interlocking said complemental members inselective adjusted positions but being shiftable out of interlockingrelation therewith for ermitting angular adjustment thereof, actuatormeans for said shiftable means, means for enabling lateral separation ofthe sections aforesaid when the sections are in one predeterminedposition relative to each other while interlocking said sections againstlateral separation in every other relative position, and a cam stopreleasably engageable with said actuator means to positively lock saidshiftable means in its normal position.

5. A laryngoscope, comprising a handle section, a blade section, andmeans hingedly and detachably interconnecting the sections includingcomplemental relatively rotatable members for enabling said bladesection to be angularly adjusted relative to said handle section,shiftable means for positively locking said complemental members inselective adjusted angular positions, cooperative abutment means on saidshiftable means and one of said rotatable members for releasably lockingsaid shiftable means in looking relation with said complemental membersto prevent shifting movement of the same in one direction, a lampcarried by said blade section, electric current supplying means carriedby said handle section, and means in said complemental members forcompleting an electrical circuit between said lamp and said currentsupplying means when the sections are in at least one position ofangular adjustment.

6. A laryngoscope as defined in claim 5, wherein the means forreleasably locking the shiftable means comprises a cam stop.

'7. A laryngoscope as defined in claim 5, wherein the shiftable meansincludes an actuator button, and the means for releasably locking theshiftable means comprises a cam stop carried by 10 one of thecomplemental members and engageable with said actuator button.

8. A laryngoscope, comprising a blade section, a handle section, and ahinge joint connecting said sections together, said hinge jointincluding complemental relatively rotatable members enabling said bladesection to be angularly adjusted relative to said handle section, eachof said complemental members being rovided with internal splines, and asplined pin shiftable into and out of cooperative relation with thesplines in one of the complemental members for selectively andpositively locking said blade section in selective adjusted positionsand for unlocking said blade section to permit angular adjustmentthereof.

9. A laryngoscope, comprising a blade section, a handle section, and ahinge joint connecting said sections together, said hinge jointincluding complemental relatively rotatable members enabling said bladesection to be angularly adjusted relative to said handle section, eachof said complemental members being provided with internal splines, ashiftable splined pin cooperative with the splines in the complementalmembers for selectively and positively locking said blade section inselective adjusted positions and for unlocking said blade section topermit angular adjustment thereof, and means in the hinge joint enablinglateral separation of the handle and blade sections aforesaid when thesections are in one predetermined position relative to each other, whileinterlocking the sections together in every other relative positiontherebetween.

10. A laryngoscope as defined in claim 9, wherein one of saidcomplemental members is provided with an annular locking ring havinginternal splines formed therein, and the shiftable splined pin comprisesa pair of axially spaced splined sections, one of said splined sectionsbeing engageable with and disengageable from said locking ring and theother of said splined sections being slidingly engaged with the splinesin the other of said complemental members.

11. A laryngoscope as defined in claim 9, wherein the shiftable splinedpin and one of the complemental members are provided with cooperativemeans for limiting shifting movement of the pin into cooperative lockingrelation with the splines in the complemental members.

12. A laryngoscope as defined in claim 9, wherein the shiftable splinedpin comprises a pair of axially spaced splined sections, one of saidsplined sections being engageable with and disengageable from thesplines in one of said complemental members, the other of said splinedsections being slidingly engaged with the splines in the other of saidcomplemental members, a stop pin carried by the last-mentioned splinedsection between two adjacent splines thereon, said stop pin beingabuttingly engageable with one of the splines in the last-mentionedcomplemental member for limiting shifting movement of the other of saidsplined sections into engagement with the splines in the first-mentionedcomplemental member.

13. A laryngoscope as defined in claim 9, wherein the shiftable splinedpin is provided with an actuator for shifting the same out ofcooperative relation with the splines in one of the complementalmembers, and resilient means interposed between said actuator and one ofthe complemental members for normally urging said pin into cooperativerelation with the splines in said one of the complemental members.

14. A laryngoscope, comprising a blade section,

a handle section, and a hinge joint connecting said sections together,said hinge joint including complemental relatively rotatable membersenabling said blade section to be angularly adjusted relative to saidhandle section, a shiftable plunger extending through said complementalmembers, mating splines on said plunger and said complemental membersrespectively, the splines on said plunger being slidingly engaged withthe splines in one of said complemental members and being shiftable intoand out of engagement with the splines of the other of said complementalmembers for selectively and positively locking said blade section inselective adjusted positions and for unlocking said sections to permitangular adjustment thereof, an actuator carried by said plunger forshifting the same out of engagement with the splines in one of thecomplemental members, resilient means interposed between said actuatorand one of the complemental members for normally urging said plungerinto engagement with the splines in said complemental members, and meansfor releasably locking said actuator when the blade is locked in aselected adjusted position.

15. A laryngoscope as defined in claim 14, wherein the means forreleasably locking said actuator comprises a cam stop carried by one ofsaid complemental members and engageable with said actuator.

16. An angularly adjustable and separable hinge joint of the classdescribed, comprising a pair of relatively rotatable complementalmembers having an axial opening therethrough, splines spaced about theperiphery of said opening in each of said complemental members, meansfor enabling selective angular adjustment of said complemental membersand for positively locking said complemental members in adjustedposition including a pin shiftably mounted in said opening and havingsplines thereon complementary to the splines in said complementalmembers for selective engagement with and disengagement from theinternal splines in one of said complemental members and for slidingengagement with the splines in the other of Said complemental members,and meanscooperative with said complemental members for enabling lateralseparation thereof when they are in one predetermined relative angularposition and interlocking said complemental members together in everyother relative angular position.

17. An angularly adjustable and separable hinge joint as defined inclaim 16, wherein the splines on the shiftable pin comprise axiallyspaced splined sections, one of said splined sections being engageablewith and disengageable from the complementary splines in one of saidcomplemental members, and the other of said splined sections beingslidable in the complementary splines of the other of said complementalmembers.

18. An angularly adjustable and separable hinge joint as defined inclaim 16, in combination with means carried by oneof the complementalmembers for selectively and positively locking the shiftable pin at thelimit of its movement eifecting engagement of the splines thereon withthe splines in both of the complemental members.

19. An instrument of the class described, comprising a handle sectionand a blade section, said to be angularly adjusted relative to saidhandle. section, laterally shiftable means cooperatively disposed insaid relatively rotatable members for.

positively locking said sections in selective adjusted positions, andmeans releasably locking said shiftable means in locking relation withsaid in one of its rotative positions,and alsohaving means restrainingthe same against lateral shifting thereof in every other rotativeposition.

20. An instrument as defined in claim 19,

wherein the shiftable means and the actuator.

are provided with cooperatively engageable means for limiting rotationof said actuator. in

one direction to said laterally shiftable positionand for limitingrotation thereof in the opposite direction to said restrained position.

21. An instrument as defined in claim 19, wherein the actuator includesan annular skirt which is laterally shiftableinto surrounding relationabout one of said complemental relatively rotatable members, said skirthaving a chordal recess therein for enabling the actuator to. belaterally shifted when in its laterally shiftable position, and saidskirt abutting against the base portion aforesaid in every otherrotative position thereof for locking said shiftable means as aforesaid.

22. An instrument of the class described, comprising a handle sectionand a blade section respectively including a base portion and a headportion, means hingedly interconnecting said. portions includingrelatively rotatable members.

for enabling said blade section to be angularly adjusted relative tosaid handle section, a shiftable plunger cooperative with said membersfor releasably locking said sections in selective adjusted positions, anactuator rotatably carried by said plunger, a limit stop carried by saidplunger and engageable with said actuator for limiting rotation thereofin opposite directions, and a skirt on said actuator engageable withsaid base portion when said actuator is atth'e limit of its rotativemovement in one direction for preventing shifting of the plungeraforesaid, said skirt'having a recess therein for enabling said actuatorand plunger to be laterally shifted when the actuator is at the limit ofits rotative movement in the opposite direction.

23. An instrument of the class described, comprising a handle unit and ablade unit, means hingedly and releasably interconnecting said units soas to enable the same to be angularly adjusted relative to each otherand to be'detached' from each other, at will, said meansincluding ashiftable pin, safety locking means for preventing shifting of said pinand consequently for preventing angular. adjustment and detachment ofsaid units, and common actuator means for shifting said pin and forcontrollingsaid safety References Cited in the file of this patentUNITED STATES PATENTS Name Date. Long' Feb. 3, 1948 Number

